In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
Q: Passage: Hardstone carving falls under the general category of glyptic art, which covers small carvings and sculpture in all categories of stone. The definition in this context of "hardstone" is unscientific and not very rigid, but excludes "soft" stones such as soapstone (steatite) and minerals such as alabaster, both widely used for carving, as well as typical stones for building and monumental sculpture, such as marble and other types of limestone, and sandstone. These are typically not capable of a fine finish in very small carvings, and would wear in prolonged use. In other contexts, such as architecture, "hard stone" and "soft stone" have different meanings, referring to actual measured hardness using the Mohs scale of mineral hardness and other measures. Some rocks used in architecture and monumental sculpture, such as granite, are at least as hard as the gemstones, and others such as malachite are relatively soft but counted as hardstones because of their rarity and fine colour.
 Link Information: none Question: What stone is rated the highest on the Mohs scale of mineral hardness?
A: 
Answer: none